The present invention relates to a method of processing seismic data signals. Seismic data are collected in order to analyse the subsurface of the Earth, in particular for hydrocarbon exploration. The data for analysing sub sea structures may be collected on land or, over water, using sea-going vessels. In order to obtain the data a seismic source which may comprise explosives (on land) or an impulse of compressed air (at sea) is provided. The signals reflected by the various layers beneath the surface of the Earth are known as traces and are sensed by a large number, typically hundreds, of sensors such as geophones on land and hydrophones at sea. The reflected signals are recorded and the results are analysed to derive an indication of the layer formations beneath the subsurface. Such indications may then be used to assess the likelihood of hydrocarbon deposits.
However, the physical formation of layers beneath the surface do not always characterise the subsurface geology sufficiently well and the likelihood of hydrocarbon deposits are not assessed as accurately as is desired.